U.S. patent number 10,887,827 [Application Number 16/145,567] was granted by the patent office on 2021-01-05 for communication message sending method and apparatus based on backoff duration.
This patent grant is currently assigned to Huawei Technologies Co., Ltd.. The grantee listed for this patent is Huawei Technologies Co., Ltd.. Invention is credited to Baokun Shan, Feng Yu, Guangwei Yu, Yinghui Yu.
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United States Patent |
10,887,827 |
Yu , et al. |
January 5, 2021 |
Communication message sending method and apparatus based on backoff
duration
Abstract
Example communication message sending methods and apparatus
based on backoff duration are described. One example method
includes that a terminal device sends an access request to a cell
to which the terminal device belongs. The terminal device monitors
a downlink control channel, and receives an access response message
based on scheduling information on the downlink control channel. If
the access response message carries a backoff access identifier,
the terminal device determines a backoff parameter corresponding to
the backoff access identifier in the access response message based
on a correspondence that is pre-stored and that is between the
backoff access identifier and the backoff parameter. The terminal
device determines backoff duration based on the backoff parameter
and an access resource interval period corresponding to the
terminal device, and sends an access request to the cell after the
backoff duration.
Inventors: |
Yu; Feng (Beijing,
CN), Shan; Baokun (Beijing, CN), Yu;
Guangwei (Beijing, CN), Yu; Yinghui (Beijing,
CN) |
Applicant: |
Name |
City |
State |
Country |
Type |
Huawei Technologies Co., Ltd. |
Guangdong |
N/A |
CN |
|
|
Assignee: |
Huawei Technologies Co., Ltd.
(Shenzhen, CN)
|
Family
ID: |
1000005285901 |
Appl.
No.: |
16/145,567 |
Filed: |
September 28, 2018 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20190037478 A1 |
Jan 31, 2019 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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PCT/CN2016/078402 |
Apr 1, 2016 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W
74/085 (20130101); H04W 72/1289 (20130101); H04W
76/18 (20180201); H04W 48/14 (20130101); H04W
74/008 (20130101) |
Current International
Class: |
H04W
72/04 (20090101); H04W 74/08 (20090101); H04W
48/14 (20090101); H04W 72/12 (20090101); H04W
76/18 (20180101); H04W 74/00 (20090101) |
References Cited
[Referenced By]
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Oct 2014 |
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Nov 2014 |
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Jun 2015 |
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Mar 2016 |
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Other References
ZTE, "Discussion on RAR and Paging for MTC enhancement", 3GPP TSG
RAN WG1 Meeting #81, Fukuoka, Japan, May 25-29, 2015, 5 pages,
R1-152963. cited by applicant .
ASUSTeK, " Consideration on random access for further MTC
enhancement", 3GPP TSG-RAN WG2 Meeting #91, Beijing, China, Aug.
24-28, 2015, 6 pages, R2-153486. cited by applicant .
Office Action issued in Chinese Application No. 201680079493.X
dated Nov. 13, 2019, 20 pages (with English translation). cited by
applicant .
R1-153486--Ericsson, "Summary of the Coexistence Evaluation Results
for DL-only LAA and DL-only Wi-Fi," 3GPP TSG RAN WG1 Meeting #81,
Fukuoka, Japan, May 25-29, 2015, 122 pages. cited by
applicant.
|
Primary Examiner: Kizou; Hassan
Assistant Examiner: Chowdhury; Mahbubul Bar
Attorney, Agent or Firm: Fish & Richardson P.C.
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation of International Application No.
PCT/CN2016/078402, filed on Apr. 1, 2016, the disclosure of which
is hereby incorporated by reference in its entirety.
Claims
The invention claimed is:
1. A communication message sending method, comprising: sending, by
a terminal device, an access request to a cell to which the
terminal device belongs; monitoring, by the terminal device, a
downlink control channel; and receiving, by the terminal device,
based on scheduling information on the downlink control channel, an
access response message that carries a backoff access identifier;
determining, by the terminal device, a backoff parameter based on a
pre-stored correspondence between the backoff access identifier and
the backoff parameter; determining, by the terminal device, based
on the backoff parameter and an access resource interval period
corresponding to the terminal device, backoff duration, wherein the
backoff duration is determined based on a product of the backoff
parameter and the access resource interval period, wherein the
access resource interval period indicates a minimum time interval
of an access resource that is available for the terminal device to
send the access request twice on an access channel of the cell; and
sending, by the terminal device, the access request to the cell
after the backoff duration.
2. The method according to claim 1, wherein before determining, by
the terminal device, based on the backoff parameter and an access
resource interval period corresponding to the terminal device,
backoff duration, the method further comprises: determining, by the
terminal device, based on a coverage degree of the cell on the
terminal device, a coverage range level of the terminal device; and
determining, by the terminal device, an access resource interval
period that is on an access channel of the cell and that
corresponds to the coverage range level of the terminal device,
wherein correspondence information between the coverage range level
and the access resource interval period is comprised in a system
message indicating physical channel resource configuration in the
cell, and is sent by the cell to the terminal device.
3. The method according to claim 2, wherein determining, by the
terminal device based on the backoff parameter and the access
resource interval period, backoff duration comprises:
Backoff_Time=[0,Backoff_Value]*Period.sub.CEL, wherein Backoff_Time
represents the backoff duration, any value selected from [0,
Backoff_Value] is the backoff parameter, and Period.sub.CEL
represents the access resource interval period corresponding to the
coverage range level of the terminal device.
4. A communication message sending method, comprising: sending, by
a terminal device, a communication message to a cell to which the
terminal device belongs; when the terminal device does not receive,
in a preset duration after the communication message is sent, a
response message sent by the cell, or when the terminal device
receives a response message that carries a backoff transmission
identifier that is sent by the cell, obtaining, by the terminal
device, a backoff parameter; determining, based on the backoff
parameter and a basic backoff timeslot corresponding to the
terminal device, backoff duration, wherein the backoff duration is
determined based on a product of the backoff parameter and the
basic backoff timeslot, wherein the basic backoff timeslot
indicates a minimum duration unit when the terminal device performs
backoff; and sending, by the terminal device, an access request to
the cell after the backoff duration.
5. The method according to claim 4, wherein before determining,
based on the backoff parameter and a basic backoff timeslot
corresponding to the terminal device, backoff duration, the method
further comprises: determining, by the terminal device, a basic
backoff timeslot corresponding to a to-be-used first channel based
on a pre-stored correspondence between each channel and a basic
backoff timeslot.
6. The method according to claim 5, wherein determining, based on
the backoff parameter and a basic backoff timeslot corresponding to
the terminal device, backoff duration comprises:
Backoff_Time=[0,CW_CH]*basic backoff timeslot, wherein Backoff_Time
represents the backoff duration, any value selected from [0, CW_CH]
is the backoff parameter, and the basic backoff timeslot represents
the basic backoff timeslot corresponding to the to-be-used first
channel.
7. A terminal device, comprising: a memory; a transceiver
configured to send an access request to a cell to which the
transceiver belongs; a processor configured to: monitor a downlink
control channel, and control, based on scheduling information on
the downlink control channel, the transceiver to receive an access
response message, when the access response message carries a
backoff access identifier, determine, a backoff parameter based on
a pre-stored correspondence stored in the memory and that is
between the backoff access identifier and the backoff parameter,
and determine backoff duration based on the backoff parameter and
an access resource interval period corresponding to the terminal
device, wherein the backoff duration is determined based on a
product of the backoff parameter and the access resource interval
period, wherein the access resource interval period indicates a
minimum time interval of an access resource that is available for
the terminal device to send the access request twice on an access
channel of the cell; and wherein the transceiver is configured to
send the access request to the cell after the backoff duration.
8. The terminal device according to claim 7, wherein the processor
is further configured to: before determining the backoff duration
based on the backoff parameter and the access resource interval
period corresponding to the terminal device, determine, based on a
coverage degree of the cell on the terminal device, a coverage
range level of the terminal device, and determine an access
resource interval period that is on the access channel of the cell
and that corresponds to the coverage range level of the terminal
device, wherein correspondence information between the coverage
range level and the access resource interval period is comprised in
a system message indicating physical channel resource configuration
in the cell, and is sent by the cell to the terminal device.
9. The terminal device according to claim 8, wherein to determine
backoff duration, the processor is configured to:
Backoff_Time=[0,Backoff_Value]*Period.sub.CEL, wherein Backoff_Time
represents the backoff duration, any value selected from [0,
Backoff_Value] is the backoff parameter, and Period.sub.CEL
represents the access resource interval period corresponding to the
coverage range level of the terminal device.
10. A terminal device, comprising: a memory; a transceiver
configured to send a communication message to a cell to which the
transceiver belongs; a processor configured to: when the
transceiver does not receive, in a preset duration after the
communication message is sent, a response message sent by the cell,
or when the transceiver receives a response message that carries a
backoff transmission identifier and that is sent by the cell,
obtain a backoff parameter, and determine, based on the backoff
parameter and a basic backoff timeslot corresponding to the
terminal device, backoff duration, wherein the backoff duration is
determined based on a product of the backoff parameter and the
basic backoff timeslot, wherein the basic backoff timeslot
indicates a minimum duration unit when the terminal device performs
backoff; and wherein the transceiver is configured to send an
access request to the cell after the backoff duration.
11. The terminal device according to claim 10, wherein the
processor is further configured to: before determining, based on
the backoff parameter and a basic backoff timeslot corresponding to
the terminal device, backoff duration, determine a basic backoff
timeslot that corresponds to a to-be-used first channel based on a
pre-stored correspondence stored in the memory between each channel
and a basic backoff timeslot.
12. The terminal device according to claim 11, wherein to determine
backoff duration, the processor is configured to:
Backoff_Time=[0,CW_CH]*basic backoff timeslot, wherein Backoff_Time
represents the backoff duration, any value selected from [0, CW_CH]
is the backoff parameter, and the basic backoff timeslot represents
the basic backoff timeslot corresponding to the to-be-used first
channel.
13. A non-transitory computer readable medium storing program codes
for use by a terminal device for sending communication messages,
wherein the program codes comprise instructions which, when
executed by a processor, cause the terminal device to: send an
access request to a cell to which the terminal device belongs;
monitor a downlink control channel, and receive, based on
scheduling information on the downlink control channel, an access
response message that carries a backoff access identifier;
determine a backoff parameter based on a pre-stored correspondence
between the backoff access identifier and the backoff parameter;
determine backoff duration based on the backoff parameter and an
access resource interval period corresponding to the terminal
device, wherein the backoff duration is determined based on a
product of the backoff parameter and the access resource interval
period, wherein the access resource interval period indicates a
minimum time interval of an access resource that is available for
the terminal device to send the access request twice on an access
channel of the cell; and send the access request to the cell after
the backoff duration.
14. A non-transitory computer readable medium storing program codes
for use by a terminal device for sending communication messages,
wherein the program codes comprise instructions which, when
executed by a processor, cause the terminal device to: send an
access request to a cell to which the terminal device belongs; when
a transceiver of the terminal device does not receive, in a preset
duration after the communication message is sent, a response
message sent by the cell, or when the transceiver receives a
response message that carries a backoff transmission identifier and
that is sent by the cell, obtain a backoff parameter; determine,
based on the backoff parameter and a basic backoff timeslot
corresponding to the terminal device, backoff duration, wherein the
backoff duration is determined based on a product of the backoff
parameter and the basic backoff timeslot, wherein the basic backoff
timeslot indicates a minimum duration unit when the terminal device
performs backoff; and send an access request to the cell after the
backoff duration.
Description
TECHNICAL FIELD
The present application relates to the field of Internet
technologies, and in particular, to a communication message sending
method and an apparatus.
BACKGROUND
Mobile communication has greatly changed people's life, but people
are still in pursuit of mobile communication with better
performance. To cope with explosive growth of mobile data traffic,
mass device connections, and various newly-emerging services and
application scenarios in the future, the 5G system will emerge as
the times require. The Internet of Things is an important part of
the 5G, and the market requirements for the Internet of Things are
rapidly increasing. Currently, the 3GPP standard focuses on bearing
an Internet of Things (IoT) service based on a cellular network, by
designing a new air-interface, and by making full use of features
of a narrowband technology. This type of IoT is referred to as the
NB-IoT. Compared with a conventional cellular network, a service
and a terminal device of the NB-IoT network have the following
features: a low rate for a service, a long period, mass
connections, low costs, low power consumption, and the like.
In the Long Term Evolution (LTE) system, a terminal establishes a
connection to a network by using a random access (RA) process at a
Media Access Control (MAC) layer. The terminal may send a preamble
sequence (which may be referred to as a preamble) to a base station
when a preset resource period is reached, so as to indicate, to the
base station, that the terminal needs to access the network. In
this case, if the base station needs to delay access from the
terminal for some reasons (for example, network overload), a BI
(backoff indicator) may be carried in an RAR (random access
response). The terminal may pre-store a correspondence table
between the BI and backoff duration, search the correspondence
table for backoff duration corresponding to the received BI, and
then re-send a preamble when the backoff duration is reached.
In a process of implementing the present application, the inventor
finds that the prior art has at least the following problem:
Different terminals may have different resource periods. In this
case, it is hard to use a unified correspondence table between the
BI and the backoff duration to control backoff access from each
terminal. This causes a relatively poor flexibility of load
control. For example, a resource period of a terminal A is 10 ms
(that is, one sending opportunity arises every 10 ms), a resource
period of a terminal B is 400 ms (that is, one sending opportunity
arises every 400 ms), and maximum backoff duration is 320 ms. A
quantity of maximum backoff sending opportunities of the terminal A
varies between 0 to 32. However, for the terminal B, maximum
backoff duration is 320 ms<400 ms. Therefore, processing of the
terminal B after the control access is the same as the processing
before the control access, and a function of controlling access
from the terminal B cannot be implemented.
SUMMARY
To implement that a terminal device effectively controls backoff
access from each terminal in a process of performing backoff
processing to improve flexibility of load control, embodiments of
the present application provide a communication message sending
method and an apparatus. The technical solutions are as
follows:
According to a first aspect, a communication message sending method
is provided, and the method includes:
sending, by a terminal device, an access request to a cell to which
the terminal device belongs;
listening to, by the terminal device, a downlink control channel,
and receiving, based on scheduling information on the downlink
control channel, an access response message;
if the access response message carries a backoff access identifier,
determining, by the terminal device based on a correspondence that
is pre-stored and that is between the backoff access identifier and
a backoff parameter, the backoff parameter corresponding to the
backoff access identifier in the access response message;
determining, by the terminal device, backoff duration based on the
backoff parameter and an access resource interval period
corresponding to the terminal device; and
re-sending, by the terminal device, an access request to the cell
after the backoff duration.
The resource interval period may indicate a minimum time interval
of an access resource that is available for the terminal device to
send the access requests twice on the access channel, that is, a
sending period used by the terminal device to send the access
request. The backoff parameter may be a multiple of the access
resource interval period.
The terminal may search the pre-stored correspondence between the
backoff access identifier and the backoff parameter for the backoff
parameter corresponding to the received backoff access identifier,
and then may multiply the backoff parameter by the resource
interval period corresponding to the terminal device to obtain the
backoff duration of the terminal device.
With reference to the first aspect, in a first possible
implementation of the first aspect, before the determining, by the
terminal device based on the backoff parameter and an access
resource interval period corresponding to the terminal device,
backoff duration, the method further includes:
determining, by the terminal device based on a coverage degree of
the cell on the terminal device, a coverage range level of the
terminal device, and determining an access resource interval period
that is on an access channel of the cell and that is corresponding
to the coverage range level of the terminal device; where
the access resource interval period indicates a minimum time
interval of an access resource that is available for the terminal
device to send the access requests twice on the access channel;
and
correspondence information between the coverage range level and the
access resource interval period is included in a system message
indicating physical channel resource configuration in the cell, and
is sent by the cell to the terminal device.
The cell (for example, a cellular cell) may send, in a form of
broadcast, the system message indicating the physical channel
resource configuration to the terminal device. The system message
may carry the correspondence information between the coverage range
level and the access resource interval period. The terminal device
may detect the coverage degree of the cell on the terminal device,
determine the coverage range level of the terminal device based on
the coverage degree, and search the foregoing correspondence for
the access resource interval period corresponding to the coverage
range level of the terminal device.
With reference to the first aspect or the first possible
implementation of the first aspect, in a second possible
implementation of the first aspect, a specific manner of the
determining, by the terminal device based on the backoff parameter
and the access resource interval period, backoff duration is:
Backoff_Time=[0,Backoff_Value]*Period.sub.CEL, where
Backoff_Time represents the backoff duration, any value selected
from [0, Backoff_Value] is the backoff parameter, and
Period.sub.CEL represents the access resource interval period
corresponding to the coverage range level of the terminal
device.
According to a second aspect, a communication message sending
method is provided, and the method includes:
sending, by a terminal device, a communication message to a cell to
which the terminal device belongs;
if the terminal device does not receive, in preset duration after
the communication message is sent, a response message sent by the
cell, or the terminal device receives a response message that
carries a backoff transmission identifier and that is sent by the
cell, obtaining, by the terminal device, a backoff parameter, and
determining, based on the backoff parameter and a basic backoff
timeslot corresponding to the terminal device, backoff duration;
and
re-sending, by the terminal device, an access request to the cell
after the backoff duration.
The basic backoff timeslot indicates a minimum duration unit when
the terminal device performs backoff. For a channel that is
distinguished by using frequency domain, a length of the basic
backoff timeslot may be an integer quantity of basic timeslots of
transmission duration of a typical data packet. For a channel that
is distinguished by using time domain, the basic backoff timeslot
may be an emergence period of a channel corresponding to each
coverage range level or MCS (Modulation and Coding Schemes,
modulation and coding scheme) in time domain.
The backoff parameter may be a multiple of the basic backoff
timeslot. The terminal device may store a backoff window, and the
backoff window may also be referred to as a contention window. The
backoff window may be a value range, and each value included in the
value range may be used as the backoff parameter. The backoff
parameter may be a multiple of the basic backoff timeslot. The
terminal device may generate a positive integer N that is not
greater than the backoff window. The backoff window may be equal to
a backoff initial window, or may be equal to a product obtained by
multiplying the backoff initial window by a quantity of times of
sending a data packet. Backoff initial windows corresponding to
different MCSs or different coverage range levels may be the same,
or may be different. If backoff initial windows corresponding to
coverage range levels are different, the foregoing system message
may carry a correspondence between the coverage range level and the
backoff initial window. The terminal device may randomly select a
value in the backoff window as the backoff parameter.
With reference to the second aspect, in a first possible
implementation of the second aspect, before the determining, based
on the backoff parameter and a basic backoff timeslot corresponding
to the terminal device, backoff duration, the method further
includes:
determining, by the terminal device based on a correspondence that
is pre-stored and that is between each channel and the basic
backoff timeslot, a basic backoff timeslot corresponding to a
to-be-used first channel; where
the basic backoff timeslot indicates a minimum duration unit when
the terminal device performs backoff.
The base station may send, in a form of broadcast, the system
message to the terminal device. The system message may carry a
correspondence between each channel and the MCS and a backoff
parameter on each channel. The backoff parameter may be a multiple
of the basic backoff timeslot. In addition, the system message may
include a basic backoff timeslot corresponding to each MCS,
retransmission times of each data packet, and the like.
Alternatively, the system message may carry a correspondence
between the coverage range level and the basic backoff timeslot.
The terminal device may determine a coverage range level
corresponding to the terminal device, and use a basic backoff
timeslot corresponding to the coverage range level as a basic
backoff timeslot of the terminal device.
For any channel, if the channel is corresponding to one MCS, a
basic backoff timeslot of the MCS is used as a basic backoff
timeslot corresponding to the channel; or if the channel is
corresponding to a plurality of MCSs, a maximum basic backoff
timeslot of basic backoff timeslots corresponding to the plurality
of MCSs is used as the basic backoff timeslot corresponding to the
channel.
With reference to the second aspect or the first possible
implementation of the second aspect, in a second possible
implementation of the second aspect, a specific manner of the
determining, based on the backoff parameter and a basic backoff
timeslot corresponding to the terminal device, backoff duration is:
Backoff_Time=[0,CW_CH]*basic backoff timeslot, where
Backoff_Time represents the backoff duration, any value selected
from [0, CW_CH] is the backoff parameter, and the basic backoff
timeslot represents the basic backoff timeslot corresponding to the
to-be-used first channel.
According to a third aspect, a terminal device is provided, where
the terminal device includes a transceiver, a processor, and a
memory, where:
the transceiver is configured to send an access request to a cell
to which the transceiver belongs;
the processor is configured to: listen to a downlink control
channel, and control, based on scheduling information on the
downlink control channel, the transceiver to receive an access
response message;
the processor is configured to: if the access response message
carries a backoff access identifier, determine, based on a
correspondence that is pre-stored in the memory and that is between
the backoff access identifier and a backoff parameter, the backoff
parameter corresponding to the backoff access identifier in the
access response message;
the processor is configured to determine backoff duration based on
the backoff parameter and an access resource interval period
corresponding to the terminal device; and
the transceiver is configured to re-send an access request to the
cell after the backoff duration.
With reference to the third aspect, in a first possible
implementation of the third aspect, the processor is further
configured to:
before determining the backoff duration based on the backoff
parameter and the access resource interval period corresponding to
the terminal device, determine, based on a coverage degree of the
cell on the terminal device, a coverage range level of the terminal
device, and determine an access resource interval period that is on
an access channel of the cell and that is corresponding to the
coverage range level of the terminal device; where
the access resource interval period indicates a minimum time
interval of an access resource that is available for the terminal
device to send the access requests twice on the access channel;
and
correspondence information between the coverage range level and the
access resource interval period is included in a system message
indicating physical channel resource configuration in the cell, and
is sent by the cell to the terminal device.
With reference to the third aspect or the first possible
implementation of the third aspect, in a second possible
implementation of the third aspect, the processor is specifically
configured to: Backoff_Time=[0,Backoff_Value]*Period.sub.CEL,
where
Backoff_Time represents the backoff duration, any value selected
from [0, Backoff_Value] is the backoff parameter, and
Period.sub.CEL represents the access resource interval period
corresponding to the coverage range level of the terminal
device.
According to a fourth aspect, a terminal device is provided, where
the terminal device includes a transceiver and a processor,
where:
the transceiver is configured to send a communication message to a
cell to which the transceiver belongs;
the processor is configured to: if the transceiver does not
receive, in preset duration after the communication message is
sent, a response message sent by the cell, or the transceiver
receives a response message that carries a backoff transmission
identifier and that is sent by the cell, obtain a backoff
parameter, and determine, based on the backoff parameter and a
basic backoff timeslot corresponding to the terminal device,
backoff duration; and
the transceiver is configured to re-send an access request to the
cell after the backoff duration.
With reference to the fourth aspect, in a first possible
implementation of the fourth aspect, the terminal device further
includes a memory, and the processor is further configured to:
before the determining, based on the backoff parameter and a basic
backoff timeslot corresponding to the terminal device, backoff
duration, determine, based on a correspondence that is pre-stored
in the memory and that is between each channel and the basic
backoff timeslot, a basic backoff timeslot corresponding to a
to-be-used first channel; where
the basic backoff timeslot indicates a minimum duration unit when
the terminal device pier forms backoff.
With reference to the fourth aspect or the first possible
implementation of the fourth aspect, in a second possible
implementation of the fourth aspect, the processor is specifically
configured to: Backoff_Time=[0,CW_CH]*basic backoff timeslot,
where
Backoff_Time represents the backoff duration, any value selected
from [0, CW_CH] is the backoff parameter, and the basic backoff
timeslot represents the basic backoff timeslot corresponding to the
to-be-used first channel.
According to a fifth aspect, a terminal device is provided, where
the terminal device includes:
a transceiver module, which may be specifically implemented by a
transceiver, configured to send an access request to a cell to
which the transceiver module belongs;
a listening module, which may be specifically implemented by a
processor, configured to: listen to a downlink control channel, and
control, based on scheduling information on the downlink control
channel, the transceiver module to receive an access response
message; and
a determining module, which may be specifically implemented by a
processor, configured to: if the access response message carries a
backoff access identifier, determine, based on a correspondence
that is pre-stored in the memory and that is between the backoff
access identifier and a backoff parameter, the backoff parameter
corresponding to the backoff access identifier in the access
response message; where
the determining module, which may be specifically implemented by a
processor, is further configured to determine backoff duration
based on the backoff parameter and an access resource interval
period corresponding to the terminal device; and
the transceiver module, which may be specifically implemented by a
transceiver, is further configured to re-send an access request to
the cell after the backoff duration.
With reference to the fifth aspect, in a first possible
implementation of the fifth aspect, the determining module is
further configured to:
before determining the backoff duration based on the backoff
parameter and the access resource interval period corresponding to
the terminal device, determine, based on a coverage degree of the
cell on the terminal device, a coverage range level of the terminal
device, and determine an access resource interval period that is on
an access channel of the cell and that is corresponding to the
coverage range level of the terminal device; where
the access resource interval period indicates a minimum time
interval of an access resource that is available for the terminal
device to send the access requests twice on the access channel;
and
correspondence information between the coverage range level and the
access resource interval period is included in a system message
indicating physical channel resource configuration in the cell, and
is sent by the cell to the terminal device.
With reference to the fifth aspect or the first possible
implementation of the fifth aspect, in a second possible
implementation of the fifth aspect, the determining module is
specifically configured to:
Backoff_Time=[0,Backoff_Value]*Period.sub.CEL, where
Backoff_Time represents the backoff duration, any value selected
from [0, Backoff_Value] is the backoff parameter, and
Period.sub.CEL represents the access resource interval period
corresponding to the coverage range level of the terminal
device.
According to a sixth aspect, a terminal device is provided, where
the terminal device includes:
a transceiver module, which may be specifically implemented by a
transceiver, configured to send a communication message to a cell
to which the transceiver module belongs; and
a determining module, which may be specifically implemented by a
processor, configured to: if the transceiver module does not
receive, in preset duration after the communication message is
sent, a response message sent by the cell, or the transceiver
receives a response message that carries a backoff transmission
identifier and that is sent by the cell, obtain a backoff
parameter, and determine, based on the backoff parameter and a
basic backoff timeslot corresponding to the terminal device,
backoff duration; where
the transceiver module, which may be specifically implemented by a
transceiver, is further configured to re-send an access request to
the cell after the backoff duration.
With reference to the sixth aspect, in a first possible
implementation of the sixth aspect, the determining module is
further configured to:
before the determining, based on the backoff parameter and a basic
backoff timeslot corresponding to the terminal device, backoff
duration, determine, based on a correspondence that is pre-stored
in the memory and that is between each channel and the basic
backoff timeslot, a basic backoff timeslot corresponding to a
to-be-used first channel; where
the basic backoff timeslot indicates a minimum duration unit when
the terminal device pier forms backoff.
With reference to the sixth aspect or the first possible
implementation of the sixth aspect, in a second possible
implementation of the sixth aspect, the determining module is
specifically configured to: Backoff_Time=[0,CW_CH]*basic backoff
timeslot, where
Backoff_Time represents the backoff duration, any value selected
from [0, CW_CH] is the backoff parameter, and the basic backoff
timeslot represents the basic backoff timeslot corresponding to the
to-be-used first channel.
The technical solutions provided in the embodiments of the present
application bring the following beneficial effects:
In this embodiment of the present application, the terminal device
sends an access request to a cell to which the terminal device
belongs; the terminal device listens to a downlink control channel,
and receives, based on scheduling information on the downlink
control channel, an access response message; if the access response
message carries a backoff access identifier, the terminal device
determines, based on a correspondence that is pre-stored and that
is between the backoff access identifier and a backoff parameter,
the backoff parameter corresponding to the backoff access
identifier in the access response message; the terminal device
determines, based on the backoff parameter and an access resource
interval period corresponding to the terminal device, backoff
duration; and the terminal device re-sends an access request to the
cell after the backoff duration. In this way, the backoff duration
may be determined based on the access resource interval period
corresponding to the terminal device, and backoff access from each
terminal may be effectively controlled, thereby improving
flexibility of load control.
BRIEF DESCRIPTION OF DRAWINGS
To describe the technical solutions in the embodiments of the
present application more clearly, the following briefly describes
the accompanying drawings required for describing the embodiments.
Apparently, the accompanying drawings in the following description
show merely some embodiments of the present application, and a
person of ordinary skill in the art may derive other drawings from
these accompanying drawings without creative efforts.
FIG. 1 is a block diagram of a system according to an embodiment of
the present application;
FIG. 2 is a flowchart of a communication message sending method
according to an embodiment of the present application;
FIG. 3 is a schematic structural diagram of a terminal device
according to an embodiment of the present application;
FIG. 4 is a flowchart of a communication message sending method
according to an embodiment of the present application;
FIG. 5 is a flowchart of a communication message sending method
according to an embodiment of the present application;
FIG. 6 is a schematic diagram of a channel according to an
embodiment of the present application;
FIG. 7 is a schematic diagram of a channel according to an
embodiment of the present application;
FIG. 8 is a schematic structural diagram of a terminal device
according to an embodiment of the present application; and
FIG. 9 is a schematic structural diagram of a terminal device
according to an embodiment of the present application.
DESCRIPTION OF EMBODIMENTS
To make the objectives, technical solutions, and advantages of the
present application clearer, the following further describes the
embodiments of the present application in detail with reference to
the accompanying drawings.
FIG. 1 shows a wireless communications system provided in this
application. An architecture of the wireless communications system
is applicable to all embodiments of this application. The method
provided in this embodiment may be applied to a licensed spectrum
in the wireless communications system such as the NB-IoT system. As
shown in FIG. 2, FIG. 2 is a block diagram of a system according to
an embodiment of the present application. The wireless
communications system may include: a network device 101 and at
least one terminal device 102. The NB-IoT system may be widely
applied in a plurality of fields, including intelligent traffic, a
building automation system, a home intelligent control system, a
video surveillance system, industrial monitoring, and the like. As
shown in FIG. 2, a refrigerator, an ammeter, a vehicle, and the
like may be used as the terminal device 102 in the NB-IoT system,
and communicate with other terminal devices by using a base
station, a transport network, or the like (which are used as the
network device 101 in the NB-IoT system), for example,
communication between the ammeter and the vehicle.
The network device 101 may include a base station or a radio
resource management device configured to control the base station,
or include the base station and the radio resource management
device configured to control the base station. The base station may
be a macro base station or a micro base station such as a small
cell and a pico cell; the base station may also be a home base
station such as an home NodeB (HNB) and an home eNodeB (HeNB); and
the base station may also include a relay node (relay) and the
like.
For example, for an LTE system such as a TDD LTE system, an FDD LTE
system, or an LTE-A system, in the wireless communications system
provided in this embodiment of the present application, the network
device 101 may be an evolved NodeB (eNodeB), and the terminal
device 102 may be UE. For a TD-SCDMA system or a WCDMA system, in
the wireless communications system provided in this embodiment of
the present application, the network device 101 may include a NodeB
(NodeB) and/or an radio network controller (RNC), and the terminal
device 102 may be UE. For a GSM system, in the wireless
communications system provided in this embodiment of the present
application, the network device 101 may include a base transceiver
station (BTS) and/or a base station controller (BSC), and the
terminal device 102 is a mobile station (MS). For a Wi-Fi system,
the network device 101 may include an access point (AP) and/or an
access controller (AC), and the terminal device 102 may be a STA
(station).
A communications standard of the wireless communications system
provided in this embodiment includes but is not limited to: Global
system for mobile communications (GSM), Code Division Multiple
Access (CDMA) IS-95, Code Division Multiple Access (CDMA) 2000,
Time Division-Synchronous Code Division Multiple Access (TD-SCDMA),
Wideband Code Division Multiple Access (WCDMA), time division
duplex-Long Term Evolution (TDD LTE), Frequency Division
Duplex-Long Term Evolution (FDD LTE), Long Term Evolution-enhanced
(LTE-advanced), personal handy-phone system (PHS), Wi-Fi, Worldwide
Interoperability for Microwave Access (WiMAX), and various future
evolved wireless communications systems.
The terminal device 102 may be a wireless terminal. The wireless
terminal may refer to a device that provides a user with voice
and/or data connectivity, a handheld device with a radio connection
function, or another processing device connected to a radio modem.
The wireless terminal may communicate with one or more core
networks through a radio access network (for example, a RAN, Radio
Access Network). The wireless terminal may be a mobile terminal,
such as a mobile phone (also referred to as a "cellular" phone) and
a computer with a mobile terminal, for example, may be a portable,
pocket-sized, handheld, computer built-in, or in-vehicle mobile
apparatus, which exchanges voice and/or data with the radio access
network. For example, it may be a device such as a personal
communication service (PCS, Personal Communication Service) phone,
a cordless telephone set, a Session Initiation Protocol (SIP)
phone, a wireless local loop (WLL) station, or a personal digital
assistant (PDA). The wireless terminal may also be referred to as a
subscriber unit, a subscriber station, a mobile station, a mobile
terminal (mobile), a remote station, an access point, a remote
terminal, an access terminal, a user terminal, a user agent, a user
device, or user equipment.
The network device 101 sends a system message in a cell (for
example, a cellular cell), where the system message may include
correspondence information between a coverage range level and an
access resource interval period. At least one terminal device 102
may receive the system message sent by the network device 101.
In addition, the at least one terminal device 102 may send an
access request to the network device 101. The network device 101
sends, for the access request, an access response message to the at
least one terminal device 102, where the access response message
may carry an access permitting identifier or a backoff access
identifier.
FIG. 3 is a schematic structural diagram of a terminal device 102
according to an embodiment of the present application. The terminal
device 102 may include a transceiver 310, a processor 320, and a
memory 330. The transceiver 310 and the memory 330 may be
separately connected to the processor 320, as shown in FIG. 3. The
transceiver 310 may be configured to send and receive messages or
data, and the transceiver 310 may include but is not limited to an
antenna, at least one amplifier, a tuner, one or more oscillators,
a coupler, an LNA (low noise amplifier), and a diplexer. The
processor 320 may be a control center of the terminal device 102,
and connects various parts of an entire server by using various
interfaces and cables. The processor 320 performs, by running or
executing a software program and/or a module that are/is stored in
the memory 330 and by invoking data stored in the memory 330,
various functions of the server, and processes data, so as to
perform overall monitoring on the terminal device 102. The
processor 320 may include one or more processing units. The
processor 320 may be a general purpose processor, including a
central processing unit (CPU), a network processor (NP), and the
like; or may be a digital signal processor (DSP), an
application-specific integrated circuit (ASIC), a field
programmable gate array (FPGA), another programmable logic
component, or the like. The memory 330 may be configured to store a
program. Specifically, the program may include program code, where
the program code includes a computer operation instruction. The
memory 330 may include a RAM, and may further include a
non-volatile memory (non-volatile memory) such as at least one
magnetic disk memory. The processor 320 executes the program code
stored in the memory 330 to implement various functions.
In this embodiment, a communication message includes any signal
that may be transmitted such as data and a sequence signal, and the
communication message may be an access probe signal preamble.
As shown in FIG. 4, a procedure of sending the communication
message provided in this embodiment may include the following
steps.
S401. A network device 101 sends, in a cell, a system message
indicating physical channel resource configuration, where the
system message related to the resource configuration carries
correspondence information between a coverage range level and an
access resource interval period on an access channel of the cell,
and the correspondence information is related to determining
backoff duration.
The resource interval period may be a sending period used by a
terminal device 102 to send an access request.
In implementation, the system message may be sent in a form of
broadcast. After receiving the correspondence information, the
terminal device 102 may store the correspondence information for
subsequent processing.
S402. After receiving the system message indicating the physical
channel resource configuration, the terminal device 102 obtains the
correspondence information between the coverage range level and the
access resource interval period in the system message. The terminal
device 102 determines, based on a coverage degree of the cell on
the terminal device 102, a coverage range level, and determines the
access resource interval period based on the correspondence
information.
S403. The terminal device 102 sends an access request on the access
channel.
S404. After receiving the access request sent by the terminal
device 102 on the access channel, the network device 101 sends, to
the terminal device 102, scheduling information of an access
response message on a downlink control channel, and sends the
access response message to the terminal device 102 based on the
scheduling information, where the access response message includes
a backoff access identifier.
S405. After receiving the access response message, the terminal
device 102 obtains the backoff access identifier in the access
response message. The terminal device 102 determines a backoff
parameter based on the backoff access identifier, and then
determines the backoff duration based on the backoff parameter and
the access resource interval period.
In implementation, the terminal device 102 may pre-store a
correspondence between the backoff access identifier and the
backoff parameter. The correspondence may be stored in a form of a
correspondence table, and the correspondence table may be as
follows:
TABLE-US-00001 BI Index Backoff Parameter Value 0 X0 1 X1 2 X2 3 X3
4 X4 5 X5 6 X6 7 X7 8 X8
The BI may be the backoff access identifier, and each of X0, X1 . .
. may be the backoff parameter corresponding to the backoff access
identifier. The backoff parameter may be a multiple of the access
resource interval period. For example, X1 may indicate that a
multiple of the access resource interval period is 1, and X8 may
indicate that a multiple of the access resource interval period is
8. The terminal device 102 may multiply the backoff parameter by
the resource interval period corresponding to the terminal device
102 to obtain backoff duration of the terminal device 102. A
specific processing manner is:
The backoff duration is determined based on a formula (1), and the
formula (1) is: Backoff_Time=[0,Backoff_Value]*Period.sub.CEL,
where
Backoff_Time represents the backoff duration, any value selected
from [0, Backoff_Value] is the backoff parameter, and
Period.sub.CEL represents the access resource interval period
corresponding to the coverage range level of the terminal
device.
S406. The terminal device 102 sends the access request on the
access channel after the backoff duration.
In implementation, the terminal device 102 may send the access
request on the access channel after the backoff duration and when
the resource interval period is reached.
In implementing backoff control on the terminal device 102, the
backoff duration is determined based on the backoff access
identifier indicated by the network device 101 and the access
resource interval period of the terminal device 102. The access
resource interval period of the terminal device 102 is related to
the coverage range level of the terminal device 102, and therefore,
backoff durations obtained by terminal devices 102 of different
coverage range levels based on the same backoff access identifier
are different. This avoids a problem in which the network device
101 cannot flexibly perform the backoff control on terminal devices
102 of different coverage range levels.
The following uses the LTE system as an example, and a processing
process of sending the communication message described above may be
as follows:
An access process is a random access process in the LTE system, and
the access channel used by the terminal is a physical random access
channel PRACH.
The system message indicating resource configuration is an SIB2,
and is sent by the base station in the cell. The base station
configures, by using the SIB2, different PRACH resource parameters
for terminals at different coverage range levels, including a PRACH
resource period (that is, the foregoing access resource period).
The foregoing PRACH resource period represents a minimum time
interval between two available PRACH resources for a terminal
device of a specific coverage range level.
The access request is an access probe signal preamble, and is sent
to the base station by the terminal on an available PRACH resource.
The probe signal preamble is a sequence signal in time domain.
The access response message is a random access response protocol
data unit (RAR PDU), and the base station may combine random access
response messages for a plurality of terminal devices into one RAR
PDU for sending. When sending the RAR PDU, the base station first
sends scheduling information of the RAR PDU in the PDCCH, and then
sends the RAR PDU on a corresponding scheduling location on the
PDSCH. If the base station needs to control the terminal to perform
backoff access for reasons such as cell overload, the base station
may provide a backoff instruction by using the RAR PDU.
An access backoff identifier is BI, and a value of each BI is
corresponding to one backoff parameter. In the LTE system, a unit
of the backoff parameter is millisecond, that is, an absolute time.
The unit used in this application is the foregoing PRACH
period.
The reason for using the PRACH resource period as a unit for
backoff is: PRACH resource periods configured by the base station
for terminals at different coverage range levels are different
because of different transmission performance. When the PPACH
period is used as a unit for backoff, for a same BI instruction, a
terminal of a higher coverage range level has longer backoff
duration, and a terminal of a lower coverage range level has
shorter backoff duration. This may achieve an objective of flexibly
performing the backoff control on terminals of different coverage
range levels, and avoids a problem that when the absolute time is
used as a unit, backoff control effects of some backoff parameters
are relatively poor for terminals of some coverage range
levels.
In addition, this embodiment provides a processing process in which
an access request preamble is sent on the PRACH, and the backoff
duration is calculated by using the BI and an access resource
interval period corresponding to a current coverage range level of
the terminal, so as to perform backoff processing. The processing
process may be as follows:
Step 1: The base station sends an SIB2 in the cell, where the SIB2
includes related parameters that are used by the base station to
perform PRACH resource configuration for terminals at different
coverage range levels and that include PRACH periods corresponding
to different coverage range levels.
Step 2: After receiving the SIB2, the base station obtains the
related parameters about the PRACH resource configuration. The
terminal determines a coverage range level of the terminal based on
a coverage degree of the cell on the terminal, and determines a
PRACH period of the coverage range level based on the related PRACH
configuration parameters in the SIB2.
Step 3: The terminal sends the preamble on the PRACH to indicate,
to the base station, that the terminal needs to perform random
access.
Step 4: After receiving the preamble sent by the terminal on the
PRACH, the base station sends the scheduling information of the RAR
PDU to the terminal on the PDCCH, and sends the RAR PDU to the
terminal at the corresponding scheduling resource location on the
PDSCH, where the PAR PDU includes the BI.
Step 5: After receiving the RAR PDU, the terminal obtains the BI in
the RAR PDU. The terminal determines the backoff parameter based on
the BI, and then determines the backoff duration based on the
backoff parameter and the access resource interval period.
The backoff duration is determined based on a formula (1), and the
formula (1) is: Backoff_Time=[0,Backoff_Value]*Period.sub.CEL,
where
Backoff_Time represents the backoff duration, any value selected
from [0, Backoff_Value] is the backoff parameter, and
Period.sub.CEL represents the PRACH period corresponding to the
coverage range level of the terminal.
Step 6: After the backoff duration, the terminal re-sends the
preamble on the PRACH to request access to the cell.
It should be rioted that, in the foregoing process, it may be
implemented that the base station flexibly performs the backoff
control on terminals at different coverage range levels in a
network or a cell that supports a plurality of coverage range
levels. However, this embodiment may also be applicable to a
network and a cell that supports only a single common coverage
range level. This provides another optimization access method, and
may effectively adapt to transmission performance in a terminal
device access process by performing the backoff control with
reference to the access resource period.
In this embodiment of the present application, the terminal device
sends an access request to a cell to which the terminal device
belongs; the terminal device listens to a downlink control channel,
and receives, based on scheduling information on the downlink
control channel, an access response message; if the access response
message carries a backoff access identifier, the terminal device
determines, based on a correspondence that is pre-stored and that
is between the backoff access identifier and a backoff parameter,
the backoff parameter corresponding to the backoff access
identifier in the access response message; the terminal device
determines, based on the backoff parameter and an access resource
interval period corresponding to the terminal device, backoff
duration; and the terminal device re-sends an access request to the
cell after the backoff duration. In this way, the backoff duration
may be determined based on the access resource interval period
corresponding to the terminal device, and backoff access from each
terminal may be effectively controlled, thereby improving
flexibility of load control.
This embodiment further provides a communication message sending
method. The method may be applied to an unlicensed spectrum in the
foregoing wireless communications system. For the system, reference
may be made to the foregoing description. Referring to FIG. 1, FIG.
1 is a block diagram of a communication message sending system
according to an embodiment of the present application. Information
transmission between a terminal device and a base station is used
as an example for description in this embodiment. Other cases are
similar to the case described herein, and details are not described
herein again. As shown in FIG. 5, a specific processing process of
the method may be as follows:
S501. The base station sends a system message.
The base station may send, in a form of broadcast, the system
message to the terminal device. The system message may carry a
correspondence between each channel and an MCS and a backoff
parameter on each channel. The backoff parameter may be a multiple
of a basic backoff timeslot. In addition, the system message may
include a basic backoff timeslot corresponding to each MCS,
retransmission times of each data packet, and the like.
Alternatively, the system message may carry a correspondence
between a coverage range level and the basic backoff timeslot.
Each channel may be corresponding to one MCS, or may be
corresponding to a plurality of MCSs.
S502. A terminal device 102 receives the system message, obtains a
correspondence between each channel and an MCS, and information
such, as a backoff parameter on the channel, and then may store the
correspondence and the information.
The terminal device 102 determines to transmit data on a
corresponding channel based on the MCS selected by the terminal
device 102.
S503. The terminal device 102 sends a communication message to the
base station.
The communication message may be an access request, or may be a
data transmission request.
S504. The base station does not successfully decode data
transmitted by the terminal device 102 and feeds back a NACK
message, or the base station may not send a message to the terminal
device 102 because of overload or because of a fault or
overload.
S505. If the terminal device does not receive, in preset duration
after the communication message is sent, a response message sent by
a cell, or the terminal device receives a response message that
carries a backoff transmission identifier and that is sent by the
cell, the terminal device obtains a backoff parameter, and
determines, based on the backoff parameter and a basic backoff
timeslot corresponding to the terminal device, backoff
duration.
In implementation, if the terminal device does not receive, in the
preset duration after the communication message is sent, the
response message sent by the cell, or the terminal device receives
the response message that carries the backoff transmission
identifier and that is sent by the cell, the terminal may determine
that backoff processing needs to be performed. The terminal device
102 determines, based on a correspondence that is pre-stored and
that is between each channel and the basic backoff timeslot, a
basic backoff timeslot corresponding to a to-be-used first channel.
For any channel, if the channel is corresponding to one MCS, a
basic backoff timeslot of the MCS is used as a basic backoff
timeslot corresponding to the channel; or if the channel is
corresponding to a plurality of MCSs, a maximum basic backoff
timeslot of basic backoff timeslots corresponding to the plurality
of MCSs is used as the basic backoff timeslot corresponding to the
channel.
The basic backoff timeslot indicates a minimum duration unit when
the terminal device 102 performs backoff.
In addition, the terminal device 102 may store a backoff window,
and the backoff window may also be referred to as a contention
window. The backoff window may be a value range, and each value
included in the value range may be used as the backoff parameter.
The backoff parameter may be a multiple of the basic backoff
timeslot. The terminal device 102 may generate a positive integer N
that is not greater than the backoff window. The backoff window may
be equal to a backoff initial window, or may be equal to a product
obtained by multiplying the backoff initial window by a quantity of
times of sending a data packet. Backoff initial windows
corresponding to different MCSs or different coverage range levels
may be the same, or may be different. If backoff initial windows
corresponding to coverage range levels are different, the foregoing
system message may carry a correspondence between the coverage
range level and the backoff initial window. The terminal device 102
may randomly select a value in the backoff window as the backoff
parameter, and a calculation manner of the backoff duration may be
as follows: Backoff_Time=[0,CW_CH]*basic backoff timeslot,
where
Backoff_Time represents the backoff duration, any value selected
from [0, CW_CH] is the backoff parameter, and the basic backoff
timeslot represents the basic backoff timeslot corresponding to the
to-be-used first channel.
For a channel that is distinguished by using frequency domain, a
length of the basic backoff timeslot may be an integer quantity of
basic timeslots of transmission duration of a typical data packet.
It is assumed that a length of a basic timeslot in a frame
structure of a physical layer is 5 ms, and a rate of the physical
layer at the coverage range level or in the MCS is 100 bps, and a
length of the typical data packet is 100 bytes. In an FDD system, a
length of the basic backoff timeslot may be calculated as follows:
100*8/100*5 ms=40 ms. In a TDD system, a length of a downlink
timeslot between two uplink basic backoff timeslots should be
considered in backoff. Referring to FIG. 6, FIG. 6 is a schematic
diagram of a mapping relationship between an MCS and a channel.
Frequency domain resources occupied by different channels are
different. The basic backoff timeslot on the channel for backoff is
equal to a result of dividing the conventional packet length by the
physical layer rate or a size of one conventional physical PDU
(protocol data unit, physical layer). For a channel 1, a channel 2,
and a channel 3, basic time units of backoff are respectively T1,
T2, and T3.
For a channel that is distinguished by using time domain, the basic
backoff timeslot may be an emergence period of a channel
corresponding to each coverage range level or MCS in time domain.
Referring to FIG. 7, FIG. 7 is a schematic diagram of a mapping
relationship between an MCS and a channel. Each MCS is
corresponding to a unique channel. Time domain resources occupied
by different channels are different. A basic time unit of backoff
on the channel is equal to an emergence period of a channel, that
is, a time interval between two adjacent channels. For a channel 1,
a channel 2, and a channel 3, basic time units of backoff are
respectively T1, T2, and T3.
The terminal device 102 may start a timer after calculating the
backoff duration.
S506. The terminal device 102 sends data when a timer reaches the
backoff duration.
In the prior art, if the terminal device determines that backoff
processing needs to be performed, the terminal device may obtain
the backoff parameter pre-stored and the basic backoff timeslot,
and then multiply the backoff parameter by the basic backoff
timeslot to obtain the backoff duration. In the prior art, basic
backoff timeslots of different terminal devices are the same, and
therefore, backoff duration calculated by different terminal
devices may be the same. This may easily cause an overlapping part
in data packet sending or resource waste.
However, in this embodiment of the present application, the
terminal device sends the communication message to the cell to
which the terminal device belongs; if the terminal device does not
receive, in the preset duration after the communication message is
sent, the response message sent by the cell, or the terminal device
receives the response message that carries the backoff transmission
identifier and that is sent by the cell, the terminal device
obtains the backoff parameter, and determines, based on the backoff
parameter and the basic backoff timeslot corresponding to the
terminal device, the backoff duration; and the terminal device
re-sends the access request to the cell after the backoff duration.
In this way, the backoff duration may be determined based on the
basic backoff timeslot corresponding to the terminal device. This
may effectively avoid a case of same backoff duration of the
terminal device, thereby avoiding an overlapping part in data
packet sending or resource waste that may easily occur.
Erased on a same technical conception, an embodiment of the present
application further provides a terminal device. As shown in FIG. 3,
the terminal device provided in this embodiment may implement a
procedure of the embodiment shown in FIG. 4 of the present
application. The terminal device includes a transceiver 310, a
processor 320, and a memory 330, where:
the transceiver 310 is configured to send an access request to a
cell to which the transceiver 310 belongs;
the processor 320 is configured to: listen to a downlink control
channel, and control, based on scheduling information on the
downlink control channel, the transceiver 310 to receive an access
response message;
the processor 320 is configured to: if the access response message
carries a backoff access identifier, determine, based on a
correspondence that is pre-stored in the memory 330 and that is
between the backoff access identifier and a backoff parameter, the
backoff parameter corresponding to the backoff access identifier in
the access response message;
the processor 320 is configured to determine backoff duration based
on the backoff parameter and an access resource interval period
corresponding to the terminal device; and
the transceiver 310 is configured to re-send an access request to
the cell after the backoff duration.
The resource interval period may indicate a minimum time interval
of an access resource that is available for the terminal device to
send the access requests twice on the access channel, that is, a
sending period used by the terminal device to send the access
request. The backoff parameter may be a multiple of the access
resource interval period.
The transceiver 310 may be configured to send the access request to
the cell to which the transceiver 310 belongs. The memory 330 may
pre-store the correspondence between the backoff access identifier
and the backoff parameter. The processor 320 may search the
correspondence for the backoff parameter corresponding to the
received backoff access identifier, and then may multiply the
backoff parameter by the resource interval period corresponding to
the terminal device to obtain the backoff duration of the terminal
device.
Optionally, the processor 320 is further configured to:
before determining the backoff duration based on the backoff
parameter and the access resource interval period corresponding to
the terminal device, determine, based on a coverage degree of the
cell on the terminal device, a coverage range level of the terminal
device, and determine an access resource interval period that is on
an access channel of the cell and that is corresponding to the
coverage range level of the terminal device; where
the access resource interval period indicates a minimum time
interval of an access resource that is available for the terminal
device to send the access requests twice on the access channel;
and
correspondence information between the coverage range level and the
access resource interval period is included in a system message
indicating physical channel resource configuration in the cell, and
is sent by the cell to the terminal device.
The cell (for example, a cellular cell) may send, in a form of
broadcast, the system message indicating the physical channel
resource configuration to the terminal device. The system message
may carry the correspondence information between the coverage range
level and the access resource interval period. The processor 320
may detect the coverage degree of the cell on the terminal device,
determine the coverage range level of the terminal device based on
the coverage degree, and search the foregoing correspondence for
the access resource interval period corresponding to the coverage
range level of the terminal device.
Optionally, the processor 320 is specifically configured to:
Backoff_Time=[0,Backoff_Value]*Period.sub.CEL, where
Backoff_Time represents the backoff duration, any value selected
from [0, Backoff_Value] is the backoff parameter, and
Period.sub.CEL represents the access resource interval period
corresponding to the coverage range level of the terminal
device.
In this embodiment of the present application, the terminal device
sends an access request to a cell to which the terminal device
belongs; the terminal device listens to a downlink control channel,
and receives, based on scheduling information on the downlink
control channel, an access response message; if the access response
message carries a backoff access identifier, the terminal device
determines, based on a correspondence that is pre-stored and that
is between the backoff access identifier and a backoff parameter,
the backoff parameter corresponding to the backoff access
identifier in the access response message; the terminal device
determines, based on the backoff parameter and an access resource
interval period corresponding to the terminal device, backoff
duration; and the terminal device re-sends an access request to the
cell after the backoff duration. In this way, the backoff duration
may be determined based on the access resource interval period
corresponding to the terminal device, and backoff access from each
terminal may be effectively controlled, thereby improving
flexibility of load control.
Based on a same technical conception, an embodiment of the present
application further provides a terminal device. As shown in FIG. 3,
the terminal device provided in this embodiment may implement a
procedure of the embodiment shown in FIG. 4 of the present
application. The terminal device includes a transceiver 310 and a
processor 320, where:
the transceiver 310 is configured to send a communication message
to a cell to which the transceiver 310 belongs;
the processor 320 is configured to: if the transceiver 310 does not
receive, in preset duration after the communication message is
sent, a response message sent by the cell, or the transceiver 310
receives a response message that carries a backoff transmission
identifier and that is sent by the cell, obtain a backoff
parameter, and determine, based on the backoff parameter and a
basic backoff timeslot corresponding to the terminal device,
backoff duration; and
the transceiver 310 is configured to re-send an access request to
the cell after the backoff duration.
The backoff parameter may be a multiple of the basic backoff
timeslot. A memory 330 may store a backoff window, and the backoff
window may also be referred to as a contention window. The backoff
window may be a value range, and each value included in the value
range may be used as the backoff parameter. The backoff parameter
may be a multiple of the basic backoff timeslot. The terminal
device may generate a positive integer N that is not greater than
the backoff window. The backoff window may be equal to a backoff
initial window, or may be equal to a product obtained by
multiplying the backoff initial window by a quantity of times of
sending a data packet. Backoff initial windows corresponding to
different MCSs or different coverage range levels may be the same,
or may be different. If backoff initial windows corresponding to
coverage range levels are different, the foregoing system message
may carry a correspondence between the coverage range level and the
backoff initial window. The processor 320 may randomly select a
value in the backoff window as the backoff parameter.
Optionally, the terminal device further includes the memory 330,
and the processor 320 is further configured to:
before the determining, based on the backoff parameter and a basic
backoff timeslot corresponding to the terminal device, backoff
duration, determine, based on a correspondence that is pre-stored
in the memory 330 and that is between each channel and the basic
backoff timeslot, a basic backoff timeslot corresponding to a
to-be-used first channel; where
the basic backoff timeslot indicates a minimum duration unit when
the terminal device pier forms backoff.
the basic backoff timeslot indicates a minimum duration unit when
the terminal device performs backoff.
The base station may send, in a form of broadcast, the system
message to the terminal device. The system message may carry a
correspondence between each channel and the MCS and a backoff
parameter on each channel. The backoff parameter may be a multiple
of the basic backoff timeslot. In addition, the system message may
include a basic backoff timeslot corresponding to each MCS,
retransmission times of each data packet, and the like.
Alternatively, the system message may carry a correspondence
between the coverage range level and the basic backoff timeslot.
The processor 320 may determine a coverage range level
corresponding to the processor 320, and use a basic backoff
timeslot corresponding to the coverage range level as a basic
backoff timeslot of the terminal device.
For any channel, if the channel is corresponding to one MCS, the
processor 320 may use a basic backoff timeslot of the MCS as a
basic backoff timeslot corresponding to the channel; or if the
channel is corresponding to a plurality of MCSs, the processor 320
may use a maximum basic backoff timeslot of basic backoff timeslots
corresponding to the plurality of MCSs as the basic backoff
timeslot corresponding to the channel.
Optionally, the processor 320 is specifically configured to:
Backoff_Time=[0,CW_CH]*basic backoff timeslot, where
Backoff_Time represents the backoff duration, any value selected
from [0, CW_CH] is the backoff parameter, and the basic backoff
timeslot represents the basic backoff timeslot corresponding to the
to-be-used first channel.
In the prior art, if the terminal device determines that backoff
processing needs to be performed, the terminal device may obtain
the backoff parameter pre-stored and the basic backoff timeslot,
and then multiply the backoff parameter by the basic backoff
timeslot to obtain the backoff duration. In the prior art, basic
backoff timeslots of different terminal devices are the same, and
therefore, backoff duration calculated by different terminal
devices may be the same. This may easily cause an overlapping part
in data packet sending or resource waste.
However, in this embodiment of the present application, the
terminal device sends the communication message to the cell to
which the terminal device belongs; if the terminal device does not
receive, in the preset duration after the communication message is
sent, the response message sent by the cell, or the terminal device
receives the response message that carries the backoff transmission
identifier and that is sent by the cell, the terminal device
obtains the backoff parameter, and determines, based on the backoff
parameter and the basic backoff timeslot corresponding to the
terminal device, the backoff duration; and the terminal device
re-sends the access request to the cell after the backoff duration.
In this way, the backoff duration may be determined based on the
basic backoff timeslot corresponding to the terminal device. This
may effectively avoid a case of same backoff duration of the
terminal device, thereby avoiding an overlapping part in data
packet sending or resource waste that may easily occur.
Based on a same technical conception, an embodiment of the present
application further provides a terminal device. As shown in FIG. 8,
the terminal device provided in this embodiment may implement a
procedure of the embodiment shown in FIG. 4 of the present
application. The terminal device includes:
a transceiver module 810, configured to send an access request to a
cell to which the transceiver module 810 belongs;
a listening module 820, configured to: listen to a downlink control
channel, and control, based on scheduling information on the
downlink control channel, the transceiver module to receive an
access response message; and
a determining module 830, configured to: if the access response
message carries a backoff access identifier, determine, based on a
correspondence that is pre-stored in the memory and that is between
the backoff access identifier and a backoff parameter, the backoff
parameter corresponding to the backoff access identifier in the
access response message; where
the determining module 830 is further configured to determine
backoff duration based on the backoff parameter and an access
resource interval period corresponding to the terminal device;
and
the transceiver module 810 is further configured to re-send an
access request to the cell after the backoff duration.
The resource interval period may indicate a minimum time interval
of an access resource that is available for the terminal device to
send the access requests twice on the access channel, that is, a
sending period used by the terminal device to send the access
request. The backoff parameter may be a multiple of the access
resource interval period.
The determining module 830 may search the pre-stored correspondence
between the backoff access identifier and the backoff parameter for
the backoff parameter corresponding to the received backoff access
identifier, and then may multiply the backoff parameter by the
resource interval period corresponding to the terminal device to
obtain the backoff duration of the terminal device. The transceiver
module 810 may be implemented by using the foregoing transceiver
310, and the listening module 820 and the determining module 830
may be implemented by using the foregoing processor 320 and memory
330.
Optionally, the determining module 830 is further configured
to:
before determining the backoff duration based on the backoff
parameter and the access resource interval period corresponding to
the terminal device, determine, based on a coverage degree of the
cell on the terminal device, a coverage range level of the terminal
device, and determine an access resource interval period that is on
an access channel of the cell and that is corresponding to the
coverage range level of the terminal device; where
the access resource interval period indicates a minimum time
interval of an access resource that is available for the terminal
device to send the access requests twice on the access channel;
and
correspondence information between the coverage range level and the
access resource interval period is included in a system message
indicating physical channel resource configuration in the cell, and
is sent by the cell to the terminal device.
The cell (for example, a cellular cell) may send, in a form of
broadcast, the system message indicating the physical channel
resource configuration to the terminal device. The system message
may carry the correspondence information between the coverage range
level and the access resource interval period. The determining
module 830 may detect the coverage degree of the cell on the
terminal device, determine the coverage range level of the terminal
device based on the coverage degree, and search the foregoing
correspondence for the access resource interval period
corresponding to the coverage range level of the terminal
device.
Optionally, the determining module 830 is specifically configured
to: Backoff_Time=[0,Backoff_Value]*Period.sub.CEL, where
Backoff_Time represents the backoff duration, any value selected
from [0, Backoff_Value] is the backoff parameter, and
Period.sub.CEL represents the access resource interval period
corresponding to the coverage range level of the terminal
device.
In this embodiment of the present application, the terminal device
sends an access request to a cell to which the terminal device
belongs; the terminal device listens to a downlink control channel,
and receives, based on scheduling information on the downlink
control channel, an access response message; if the access response
message carries a backoff access identifier, the terminal device
determines, based on a correspondence that is pre-stored and that
is between the backoff access identifier and a backoff parameter,
the backoff parameter corresponding to the backoff access
identifier in the access response message; the terminal device
determines, based on the backoff parameter and an access resource
interval period corresponding to the terminal device, backoff
duration; and the terminal device re-sends an access request to the
cell after the backoff duration. In this way, the backoff duration
may be determined based on the access resource interval period
corresponding to the terminal device, and backoff access from each
terminal may be effectively controlled, thereby improving
flexibility of load control.
Based on a same technical conception, an embodiment of the present
application further provides a terminal device. As shown in FIG. 9,
the terminal device provided in this embodiment may implement a
procedure of the embodiment shown in FIG. 4 of the present
application. The terminal device includes:
a transceiver module 910, configured to send a communication
message to a cell to which the transceiver module 910 belongs;
and
a determining module 920, configured to: if the transceiver module
does not receive, in preset duration after the communication
message is sent, a response message sent by the cell, or the
transceiver receives a response message that carries a backoff
transmission identifier and that is sent by the cell, obtain a
backoff parameter, and determine, based on the backoff parameter
and a basic backoff timeslot corresponding to the terminal device,
backoff duration; where
the transceiver module 910 is further configured to re-send an
access request to the cell after the backoff duration.
The basic backoff timeslot indicates a minimum duration unit when
the terminal device performs backoff. For a channel that is
distinguished by using frequency domain, a length of the basic
backoff timeslot may be an integer quantity of basic timeslots of
transmission duration of a typical data packet. For a channel that
is distinguished by using time domain, the basic backoff timeslot
may be an emergence period of a channel corresponding to each
coverage range level or MCS in time domain.
The backoff parameter may be a multiple of the basic backoff
timeslot. The terminal device may store a backoff window, and the
backoff window may also be referred to as a contention window. The
backoff window may be a value range, and each value included in the
value range may be used as the backoff parameter. The backoff
parameter may be a multiple of the basic backoff timeslot. The
terminal device may generate a positive integer N that is not
greater than the backoff window. The backoff window may be equal to
a backoff initial window, or may be equal to a product obtained by
multiplying the backoff initial window by a quantity of times of
sending a data packet. Backoff initial windows corresponding to
different MCSs or different coverage range levels may be the same,
or may be different. If backoff initial windows corresponding to
coverage range levels are different, the foregoing system message
may carry a correspondence between the coverage range level and the
backoff initial window. The determining module 910 may randomly
select a value in the backoff window as the backoff parameter. The
transceiver module 910 may be implemented by using the foregoing
transceiver 310, and the determining module 920 may be implemented
by using the foregoing processor 320 and memory 330.
Optionally, the determining module 920 is further configured
to:
before the determining, based on the backoff parameter and a basic
backoff timeslot corresponding to the terminal device, backoff
duration, determine, based on a correspondence that is pre-stored
in the memory and that is between each channel and the basic
backoff timeslot, a basic backoff timeslot corresponding to a
to-be-used first channel; where
the basic backoff timeslot indicates a minimum duration unit when
the terminal device performs backoff.
The base station may send, in a form of broadcast, the system
message to the terminal device. The system message may carry a
correspondence between each channel and the MCS and a backoff
parameter on each channel. The backoff parameter may be a multiple
of the basic backoff timeslot. In addition, the system message may
include a basic backoff timeslot corresponding to each MCS,
retransmission times of each data packet, and the like.
Alternatively, the system message may carry a correspondence
between the coverage range level and the basic backoff timeslot.
The determining module 920 may determine a coverage range level
corresponding to the determining module 920, and use a basic
backoff timeslot corresponding to the coverage range level as a
basic backoff timeslot of the terminal device.
For any channel, if the channel is corresponding to one MCS, the
determining module 920 may use a basic backoff timeslot of the MCS
as a basic backoff timeslot corresponding to the channel; or if the
channel is corresponding to a plurality of MCSs, the determining
module 920 may use a maximum basic backoff timeslot of basic
backoff timeslots corresponding to the plurality of MCSs as the
basic backoff timeslot corresponding to the channel.
Optionally, the determining module 920 is specifically configured
to: Backoff_Time=[0,CW_CH]*basic backoff timeslot, where
Backoff_Time represents the backoff duration, any value selected
from [0, CW_CH] is the backoff parameter, and the basic backoff
timeslot represents the basic backoff timeslot corresponding to the
to-be-used first channel.
In the prior art, if the terminal device determines that backoff
processing needs to be performed, the terminal device may obtain
the backoff parameter pre-stored and the basic backoff timeslot,
and then multiply the backoff parameter by the basic backoff
timeslot to obtain the backoff duration. In the prior art, basic
backoff timeslots of different terminal devices are the same, and
therefore, backoff duration calculated by different terminal
devices may be the same. This may easily cause an overlapping part
in data packet sending or resource waste.
However, in this embodiment of the present application, the
terminal device sends the communication message to the cell to
which the terminal device belongs; if the terminal device does not
receive, in the preset duration after the communication message is
sent, the response message sent by the cell, or the terminal device
receives the response message that carries the backoff transmission
identifier and that is sent by the cell, the terminal device
obtains the backoff parameter, and determines, based on the backoff
parameter and the basic backoff timeslot corresponding to the
terminal device, the backoff duration; and the terminal device
re-sends the access request to the cell after the backoff duration.
In this way, the backoff duration may be determined based on the
basic backoff timeslot corresponding to the terminal device. This
may effectively avoid a case of same backoff duration of the
terminal device, thereby avoiding an overlapping part in data
packet sending or resource waste that may easily occur.
A person of ordinary skill in the art may understand that all or
some of the steps of the embodiments may be implemented by hardware
or a program instructing related hardware. The program may be
stored in a computer-readable storage medium. The storage medium
may include: a read-only memory, a magnetic disk, or an optical
disc.
The foregoing descriptions are merely example embodiments of the
present application, but are not intended to limit the present
application. Any modification, equivalent replacement, and
improvement made without departing from the principle of the
present application shall fall within the protection scope of the
present application.
* * * * *